U.S. Pat. No. 3,223,000 issued Dec. 14, 1965 to Payne et al describes a hydraulic gun control system having a pressure differential sensing valve to automatically increase fluid pressure in the system to satisfy all load requirements encountered in the operation and control of the gun. In particular, this system is said to permit adequate traversing of a heavy gun in all types of terrain from level to inclined without stalling.
U.S. Pat. No. 3,636,789 issued Jan. 25, 1972 to Geiger describes a gear drive mechanism for armored turrets, rotary ring gun carriages and similar weapons wherein oppositely driven spur gears are placed in engagement with a counter gear directly coupled to the weapon elevation or traversing mechanism to provide play-free drive thereof.
There exists a need for a weapon elevation mechanism characterized as having weapon balancing means to offset variable forces generated in the mechanism by changes in the elevation of the weapon, having significantly reduced breakaway friction to improve low speed tracking and reduce dynamic errors when operating in the stabilized mode, having fewer and simpler components with elimination of hydraulic motor and speed reduction gearing and having a compact size and envelope compatible with restricted turret configurations.